'Sheer majesty'

Starbucks said the drink consisted of "a sweet dusting of pink powder, blended into a creme Frappuccino with mango syrup and layered with a pleasantly sour blue drizzle. It is finished with vanilla whipped cream and a sprinkle of sweet pink and sour blue powder topping."

Twitter user Dragoneer said: "My god. @Starbucks has a UNICORN FRAPPUCINO? This is so freakin' amazing I do not have words to describe its sheer majesty."

Another, Mair wrote: "Gutted that the Starbucks unicorn frappucino is a US only thing, they look so cool :ccccc."

But some Twitter users were a little more scathing about the concoction. Baillie Starnes tweeted: "If you care anything at all about your health, sugar intake, or the life of a barista, do not order this."

According to CNN Money, a "tall" Unicorn Frappuccino with whole milk has 280 calories, 11 grammes of fat, and 39 grammes of sugar.

That's more calories than a typical jam doughnut, or three dark chocolate digestive biscuits.

The coffee giant plans to sell the drinks in the US, Mexico and Canada between 19 April and 23 April.